1. Field of the Invention
The present invention relates to a molding heater and a fabrication method thereof, and more particularly, to a molding heater for heating a semiconductor wafer and a fabrication method thereof.
2. Description of the Related Art
In processes of manufacturing a semiconductor device, such as chemical vapor deposition (CVD), sputtering, plasma etching and the like, heating of the semiconductor wafer is essential. The heating of the semiconductor wafer can be implemented by mounting a hot wire within a supporting plate on which the semiconductor wafer is placed.
FIGS. 1 and 2 are schematic views of a conventional heater. Referring to FIGS. 1 and 2, the conventional heater includes a first metal plate 10a, a second metal plate 10b and a heater wire 20. The heater wire 20 also includes a hot wire 20a, an insulator (MgO) 20b surrounding the hot wire 20a, and a metal tube 20c surrounding the insulator (MgO) 20b. The heater wire 20 is mounted within a groove that is elongatedly formed on a contact surface of the metal plates 10a and 10b. A filler 30 is interposed between the heater wire 20 and the metal plates 10a and 10b in order to increase an adhesion efficiency.
If the hot wire 20a is directly contacted with the metal plates 10a and 10b, the hot wire 20a becomes electrically shorted to the metal plates 10a and 10b. Therefore, in order to prevent this phenomenon, the hot wire 20a is disposed on the middle of an inner space of the metal tube 20c and a space between the metal tube 20c and the hot wire 20a is filled with the insulator (MgO) 20b. Since the insulator (MgO) 20b is in a powdered form, if there is not the metal tube 20c, the insulator (MgO) 20b is fragile. The first metal plate 10a and the second metal plate 10b are joined together using a welding process or a blazing process.
In the above-described conventional heater, since the hot wire 20a is surrounded with a dual layer consisting of the insulator (MgO) 20b and the metal tube 20c, a large amount of power is consumed to transfer a heat generated at the hot wire 20a to the metal plates 10a and 10b. Accordingly, the hot wire 20a is easy to break due to an overheat of the hot wire 20a. Heat conduction is hindered at both the insulator (MgO) 20b itself and the contact surface between the metal tube 20c and the metal plates 10a and 10b. 
The insulator (MgO) 20b contains moisture while being filled. To this end, in case where the heat is generated at the hot wire 20a, a corresponding portion is expanded, so that a burst of the metal tube 20c may occur. Therefore, in order to discharge the moisture and gas generated inside the metal tube 20c to an outside of the metal tube 20c, it is necessary to perform an outgassing process for a long time.
If the blazing process is used as a coupling method of the metal plates 10a and 10b, a contamination may be caused during the process due to a reaction of material used in the blazing process, and the blazing material may be etched during an in-situ cleaning process. Further, in case of the welding process, since a welding surface is formed on lateral sides of the metal plates 10a and 10b, a deformation may be caused due to a heat stress of the metal plates 10a and 10b when a temperature rises or falls.
Therefore, the present invention has been devised to solve the above problems, and it is an object of the present invention to provide a molding heater capable of minimizing a heat resistance layer that disturbs a heat conduction, thereby improving a generation of heat, preventing a short of a hot wire caused by an overload, in which it is unnecessary to perform an outgassing process.
It is another object of the invention to provide a fabrication method of a molding heater.
To achieve the aforementioned object of the present invention, there is provided a molding heater comprising: a first metal plate having a recess formed at one side and a flat surface formed at the other side, wherein a groove is formed at a lower portion of the recess and a wafer is placed on the flat surface formed on one side thereof and a groove elongatedly formed on a lower portion of the recess; a hot wire inserted into the groove; a ceramic filled in a gap between the hot wire and the groove; and a second metal plate coupled with the first metal plate, the second metal plate filling the recess while closely contacting with the lower portion and lateral sides of the recess.
To achieve the another object of the invention, there is provided a method for fabricating a molding heater, comprising the steps of: a) providing a first metal plate having a recess formed at one side and a flat surface formed at the other side, wherein a groove is formed at a lower portion of the recess and a wafer is placed on the flat surface; b) inserting a hot wire into the groove; c) filling a gap between the hot wire and the groove with a ceramic; and d) coupling a second metal plate with the first metal plate, the second metal plate filling the recess while the second metal plate closely contacts with the lower portion and lateral sides of the recess.